UnitedHealth Group said Thursday it is cooperating with civil and criminal requests from the United States Department of Justice over its Medicare practices. The Wall Street Journal reported in May that the U.S. Department of Justice is investigating the Minnesota-based company for criminal Medicare fraud.

This comes after a civil probe into UnitedHealth the newspaper reported earlier this year and a series of articles about the company’s billing practices. The Wall Street Journal found UnitedHealth had received billions of dollars from Medicare for diagnoses that some doctors said were incorrect or irrelevant. Wall Street Journal reporter Anna Mathews joined Minnesota Now to talk about the reporting.